A device which allows chemical reaction in a microreactor is disclosed by Japanese Patent Laid-Open No. 2000-298079. In this chemical reactor, one flow channel to induce reaction is provided for each liquid. In this method, however, it is difficult to increase the microreactor's throughput on a per-cubic-volume basis. In the reactor, there is only one pair of flow channels and it is easy to separate two liquids which are used for reaction.
Patent Document: Japanese Patent Laid-Open No. 2000-298079
When the sheath flow technique is used for chemical reaction between liquids, a smaller sheath flow width leads to a higher reaction speed. However, when the sheath flow width decreases, the throughput per unit time decreases. Therefore, it is desirable to form multiple sheath flows. After chemical reaction has been made using multiple sheath flows, the two liquids must be separated. However, since they have to be separated outside the microreactor, or in a macro structure, the overall chemical reaction speed will decline.